Evidence for a beta-decaying 1/2- isomer in 71Ni

TL;DR

This paper presents evidence for a beta-decaying 1/2- isomer in 71Ni, identified through reanalysis of beta-decay data, Coulomb excitation, and nuclear-structure considerations, revealing new insights into nuclear states in this isotope.

Contribution

It provides the first evidence of a beta-decaying 1/2- isomer in 71Ni and clarifies its population mechanism through combined experimental and theoretical analysis.

Findings

Identification of a 1/2- isomer in 71Ni

Observation of the isomer's beta decay with a half-life of 2.34 seconds

Reanalysis of beta-gamma coincidences supports the isomer's existence

Abstract

We report on the investigation of the population mechanism for the 454-KeV level in 71Cu. This level was identified for the first time in a recent Coulomb excitation measurement with a radioactive beam of 71Cu. The selective nature of the Coulomb-excitation process as well as nuclear-structure considerations constrain the possible spin values for the newly observed state to Ipi=1/2-. A re-examination of the data set obtained in a beta-decay study at the LISOL separator revealed that this state is also populated in the decay of 71Ni, most probably by direct feeding from a newly identified 1/2- beta-decaying isomer having a T1/2=2.34(25) s. In this paper we investigate the proposed scenario by reanalyzing the beta-gamma and gamma-gamma coincidences obtained in the beta-decay study at LISOL.